


Once Catalysed

by randomscientist



Category: Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: M/M, Pre-Relationship, Quietly Pining Mycroft
Language: English
Status: Completed
Published: 2018-12-20
Updated: 2018-12-20
Packaged: 2019-09-23 14:50:13
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,617
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17082377
Author URL: https://archiveofourown.org/users/randomscientist/pseuds/randomscientist
Summary: Sherlock makes demands upon the detective inspector frequently and without reservation.Requests, however, are much rarer occurrences, and never has one carried as much weight as the simple words he is about to say.





	Once Catalysed

He hesitates before he calls after the man starting to stride away.

There are few people in his life that Sherlock really trusts, that he could count on with his own existence. Fewer still, that he would with his brother’s, that would dependably look out for Mycroft not out of obligation, but genuine concern.

Just one, perhaps.

One that he knows his brother also regards highly. Regards with respect, and..something else. Something that causes Sherlock the brother to wrinkle his nose and turn away in distaste, but that Sherlock as a detective reads carefully, mentally jotting down as information potentially of use.

The number of occasions when a black saloon would materialise near the crime scene, doubtless carrying his lump of a brother in it, even when it needn’t have. The at first improbable observation that Mycroft, who has long perfected his methods of negotiation, who habitually exploits eye contact to intimidate or persuade, rather often seems to leave it all behind when conversing with DI Lestrade, his practised air of cold, unassailable authority dissipating like vapour in a spot of sun.

There could’ve been alternative explanations, of course, for his brother’s uncharacteristic behaviour. After all, gratitude features frequently in Mycroft’s eyes as they gaze into those of the detective inspector. A (barely perceptible) glimmer of amusement or humour too, at times, which could well be reason enough. Lestrade is an honourable man. Kind, resistant to intimidation, moderately intelligent, and not nearly as annoying as the rest of Scotland Yard. An affinity towards his company would not be inconceivable, even for Mycroft.

But twice Sherlock has caught his brother looking at the detective inspector from a distance away, something unreadable crossing his expression. He’d close his eyes for a moment fractionally longer than a blink, almost as though pained, before he would have the steely mask back in place and resume his default self — Mycroft Holmes, epitome of professionalism and composure (pfft, he thinks).

A most notable piece of evidence remains that encounter in the hospital, several years ago. Lestrade had taken a bullet during the resolution of a particularly vicious case (and it wasn’t entirely Sherlock’s fault). The surgery was said to be successful, and Sherlock was heading to the first-floor café with John when they spotted the familiar figure hovering about.

Sherlock’s comment on his brother’s obvious state of distress (he had to have been clenching that umbrella with some force for at least the past three hours, by the looks of those knuckles) was swiftly cut off by Mycroft stating that he happened to be in the hospital on a business matter, that he’d only just been informed of the unfortunate incident, and that he sent his well wishes but should best be going, if they would excuse him. Mycroft left the building shortly after, before the general anaesthetic in the detective inspector’s system had time to wear off.

The clues are fleeting and well-concealed, so sparsely given away over the years that even the only consulting detective in the world might have dismissed them as anomalies in a larger data set, had he not also shared a last name and childhood with the subject being observed. Given which (loathsome) fact, Sherlock sees the situation plain and clear — it hasn’t been a difficult deduction to make.

Sherlock isn’t certain when his brother’s..affection has developed. The earliest traces to register on Sherlock’s detective senses had been as far back as before he even took up residence in Baker Street. He had admittedly been fairly preoccupied with self-administered chemicals around the time of his brother and Lestrade’s initial acquaintance with each other, but surely, _surely_ it couldn’t have been present from the beginning. Eleven years sounds like an implausibly long time to be accommodating something of magnitude such as this (if Sherlock has estimated correctly), even in Mycroft.

 _Caring is not an advantage, Sherlock_ , were his brother’s own warning words, filed inside Sherlock’s Mind Palace since far before he could fully comprehend its significance. For most of his life Sherlock had assumed it to be another indirect declaration of Mycroft’s patronising superiority. Realisation cemented itself eventually, though half-hearted. And he has not forgotten the intensity in those tired grey eyes as his brother asked Sherlock to promise him that there would always be a list. _Promise him_ that, at least _,_ if he refused to agree to anything else.

(Mycroft does tend to overreact. It was merely a slight overestimation of his desired dose, and in Sherlock’s defence, the combined effects and interactions of multiple drugs were highly tricky to predict with any degree of accuracy.)

Only one person in the world had ever been able to evoke as much emotion in Mycroft’s gaze, if any. (Sherlock detested it.) Until there were two. And Sherlock hears the unspoken half of that sentence with increasing clarity.

_Caring is not an advantage, Sherlock. I only hope that you do not become as afflicted with the condition as I have been cursed to be._

The detective inspector is completely oblivious, of course. The man’s straightforward enough to read. Works long hours, personal life barely existent. One short-lived relationship after his divorce. Cautious, but not opposed. And if his witty remarks in an attempt to earn a quirk in the corner of Mycroft’s mouth (proven effective, often receiving dry humour in response), and the occasional element of appraisal when he looks at Mycroft, the way his gaze would travel down to Mycroft’s legs and back (ugh, perhaps Sherlock should've had it deleted after all) are anything to go by..

Has his brother been too blinded by his own (multitude of, knowing Mycroft) constraining presuppositions to _see_ what need not be, and what might in its stead?

It is objectively feasible for an eventuality to be reached. The potential is there, whispers of a latent drive. Like a thermodynamically favourable chemical reaction. The equilibrium of the process lies far to the side of synthesis, an unrivalled harmony, but sometimes, sometimes with the activation energy too high, the resistance too ingrained, for it to proceed on its own. The kinetics struggling on too slow a time scale to ever culminate in completeness and splendour within any earthly duration at all. Something has to give first. To break. To venture out of a comfortable well of being stable and secure.

Sometimes all it needs is a catalyst.

He owes his brother that much. Far too much than he cares to admit, than he knows can ever possibly be repaid (not that Mycroft expects to be recompensed for his meddling ways, and not that it would ever be made known to Mycroft, that Sherlock has capacity to feel marginally grateful, lest Mycroft’s titanic ego undergo further expansion).

Mycroft has been a constant in his life, acting the role of a responsible adult since they were children, growing up quickly so that Sherlock didn’t have to. Mycroft has always watched over him. Always been prepared to clean up whatever consequences Sherlock’s latest adventures might bring about.

Mycroft makes it far too easy to take it all for granted.

But Sherlock is not six, fourteen, or twenty-two any more, nor completely without conscience, much as he is compelled to act it when confronting his brother, defending his own rights as a free spirit in a never-ending protest (he did have reason to be resentful, and stands by his defiance). Contrary to what Sherlock’s less considerate actions consistently suggest, and how his spiteful words have been sharpened to take aim, he doesn’t _actually_ take great pleasure in seeing his brother miserable and alone.

Sherlock knows his brother. Knows his need for privacy, his general mistrust of people and disdain for attachment, how little it takes to incite unease beneath his calm. Knows that Mycroft takes solace in solitude, and would request to be left alone, now, especially now. To erase any hint of distress from his face, repress the turmoil securely locked inside. Check his attire to ensure that there is not a thread or wrinkle out of place. Only then, would he step into the world and present himself, chin high, back straight, and shoulders squared, collected and in control, the only image he would accept.

Yet Sherlock also knows, that underneath everything, despite everything, there is someone in Mycroft’s heart that he dares not allow himself to want. And that he would appreciate keenly, a gentle hand upon his shoulder, a warm presence by his side.

Not anyone’s. Never anyone’s. Just the one.

“Mycroft. Make sure he’s looked after,” he says finally, “He's not as strong as he thinks he is.”

The response he receives is accompanied by a firm nod. There are brief words of reassurance, and Sherlock reads the rest of what is promised in the steady gaze holding his own. He sees the seriousness in them, even in the dark of the night, dimly lit only by the scatter of police cars around them.

As the detective inspector turns to leave, something in Sherlock seems to settle. An overlooked part of him that he wasn’t aware had been restless until now. Like a resonant sound that’s been present in the background since sometime bygone, minor enough that he’s grown accustomed to and no longer hears, suddenly muted, surprising him with a pleasant quiet.

The catalysis is complete, marking the initiation of a fresh new stage, in something that has struggled in resistance for far too long. Being an experimental scientist by training, Sherlock Holmes isn’t naïve enough to envisage an easy, unobstructed path for his brother’s private life, forwards and onwards, but he would trust the reaction to take its course.

Greg Lestrade is a man of his words, after all.

**Author's Note:**

> May be read as a sequel to [Inconsequential](https://archiveofourown.org/works/16140704). I had the same Sherlock in mind — aged and matured by two decades and eleven years — whilst writing..
> 
> With best wishes for a lovely Christmas and New Year to anyone who might see this xx


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